Plastic anisotropy and the role of non-basal slip in magnesium alloy AZ31B
Plastic anisotropy and the role of non-basal slip in magnesium alloy AZ31B
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DOI：
10.1016/j.ijplas.2004.05.018
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发表时间：
2005-01-01
影响因子：
9.8
通讯作者：
Duygulu, Ö
中科院分区：
文献类型：
--
作者：
Agnew, SR;Duygulu, Ö
利用实验和模拟技术相结合的方法，对一种变形镁合金的塑性行为进行了力学解释。通过在一系列温度（室温至250℃）和应变速率（10⁻⁵ - 0.1 s⁻¹）下对不同取向的试样进行拉伸试验，系统地研究了影响实际板材成形性的参数，如应变硬化率、应变速率敏感性、各向异性程度以及断裂时的应力和应变。多晶塑性模拟用于对观察到的各向异性和织构演变进行建模。在低温下观察到的强烈面内各向异性归因于初始织构以及具有<u>位错矢量类型</u>（此处“dropadrop”可能是特定专业词汇有误，猜测可能是某种位错矢量类型表述）的位错比预期更大的非基面交滑移。通过透射电子显微镜对位错微观结构的直接观察，进一步验证了测量和模拟的各向异性及织构之间的一致性。随着温度升高，延展性增加，同时伴随着流动应力降低、应变速率敏感性增加以及正各向异性降低。多晶模拟表明，非基面<u>位错类型（此处“dropc + adrop”可能有误）</u>位错活动的增加为观察到的各向异性随温度升高而发生的变化提供了一种自洽的解释。（C）2004 Elsevier Ltd.保留所有权利。
Mechanistic explanations for the plastic behavior of a wrought magnesium alloy are developed using a combination of experimental and simulation techniques. Parameters affecting the practical sheet formability, such as strain hardening rate, strain rate sensitivity, the degree of anisotropy, and the stresses and strains at fracture, are examined systematically by conducting tensile tests of variously oriented samples at a range of temperatures (room temperature to 250 degreesC and strain rates (10(-5)-0.1s(-1)). Polycrystal plasticity simulations are used to model the observed anisotropy and texture evolution. Strong in-plane anisotropy observed at low temperatures is attributed to the initial texture and the greater than anticipated non-basal cross-slip of dislocations with dropadrop type Burgers vectors. The agreement between the measured and simulated anisotropy and texture is further validated by direct observations of the dislocation microstructures using transmission electron microscopy. The increase in the ductility with temperature is accompanied by a decrease in the flow stress, an increase in the strain rate sensitivity, and a decrease in the normal anisotropy. Polycrystal simulations indicate that an increased activity of non-basal, dropc + adrop, dislocations provides a self-consistent explanation for the observed changes in the anisotropy with increasing temperature. (C) 2004 Elsevier Ltd. All rights reserved.